The NFL submitted an amicus curiae brief to the Supreme Court on Thursday in support of state regulations over sports event contracts. The filing signals the league's position that states should retain authority to oversee these products rather than federal preemption.

The NFL's entry into the legal fight gives states a high-profile ally in any Supreme Court case over whether federal or state law governs sports event contracts. A ruling for state authority could fragment the regulatory landscape and force platforms like Kalshi to navigate 50 separate regimes.